Single layer zinc alloy plated steel material exhibiting excellent spot weldability and corrosion resistance, and fabrication method therefor

Patent metadata

Field	Value
Publication number	US-11203802-B2
Application number	US-201716472475-A
Country	US
Kind code	B2
Filing date	Dec 21, 2017
Priority date	Dec 26, 2016
Publication date	Dec 21, 2021
Grant date	Dec 21, 2021

Abstract

Provided are a single layer zinc alloy plated steel material and a fabrication method therefor, the single layer zinc alloy plated steel material comprising a base iron and a zinc alloy plating layer formed on the base iron, wherein the zinc alloy plating layer contains 13-24 wt % of Mg, and the adhesion amount of the zinc alloy plating layer is at most 40 g/m2 (excluding 0 g/m2).

First claim

The invention claimed is:

1. A single layer zinc alloy plated steel comprising:
a base steel and a zinc alloy plating layer disposed on the base steel,
wherein the zinc alloy plating layer includes 13 to 24 wt % of magnesium (Mg), a plating amount of the zinc alloy plating layer is 40 g/m 2 or less (excluding 0 g/m 2 ), and an average grain size of crystal grains constituting the zinc alloy plating layer is 100 nm or less (excluding 0 nm).

2. The single layer zinc alloy plated steel of claim 1 , wherein the zinc alloy plating layer comprises 15.7 to 20 wt % of Mg.

3. The single layer zinc alloy plated steel of claim 1 , wherein the plating amount of the zinc alloy plating layer is 10 to 35 g/m 2 .

4. The single layer zinc alloy plated steel of claim 1 , wherein, when a GDS profile on a central portion of the zinc alloy plating layer in a thickness direction is measured, a deviation of Mg content is within ±5%.

5. The single layer zinc alloy plated steel of claim 1 , wherein, during spot welding of the single layer zinc alloy plated steel, a zinc alloy plating layer on a welded portion is changed to an alloy layer comprising 90% or more by area (including 100% by area) of MgZn 2 alloy phase.

6. The single layer zinc alloy plated steel of claim 1 , wherein an average length of Type B cracks in the single layer zinc alloy plated steel is 0.1 time or less a base steel thickness when spot welding is performed according to SEP 1220-2 standard.

7. The single layer zinc alloy plated steel of claim 1 , wherein the base steel comprises, by weight %, 0.10 to 1.0% of carbon (C), 0.5 to 3% of silicon (Si), 1.0 to 25% of manganese (Mn), 0.01 to 10% of aluminum (Al), 0.1% or less (excluding 0%) of phosphorus (P), 0.01% or less (excluding 0%) of sulfur (S), and remainders of iron (Fe) and unavoidable impurities.

8. The single layer zinc alloy plated steel of claim 7 , wherein the contents of C, Si, Mn, P and S contained in the base steel satisfy the following relational expression 1:
[C]+[Mn]/20+[Si]/30+2[P]+4[S]≥0.3, where [C], [Mn], [Si], [P] and [S] are the contents (weight %) of respective elements.

9. The single layer zinc alloy plated steel of claim 7 , wherein the base steel comprises one or more of austenite and retained austenite as a microstructure.

Assignees

• Posco

Inventors

• Kwak Young-Jin
• Kim Tae-Yeob

Classifications

• C23C14/16 Primary

  on metallic substrates or on substrates of boron or silicon · CPC title

• C22C38/04

  containing manganese · CPC title

• C23C14/14

  Metallic material, boron or silicon · CPC title

• C23C30/00

  Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process (C23C26/00, C23C28/00 take precedence) · CPC title

• C23C14/50

  Substrate holders · CPC title